This exploratory, nonclinical study evaluated the user experience of an online acceptance and commitment therapy program for anxiety. Forty young Australian adults aged between 18 to 25 years old completed the online program over 2 weeks. System usability and perceived helpfulness were evaluated at posttest. Self-rated levels of anxiety, depression, stress, and psychological flexibility were measured at pretest, posttest, and 2-week follow up. System usability was rated above average and significant improvements were found on all mental health measures from pretest to follow-up, except for stress. These results warrant further scrutiny in a clinical randomized controlled trial on the intervention.